One common seat construction, equipped with an integrated headrest, is manufactured using a full steel seat frame to which seat cushions, backrest cushions, upholstery, and in some applications, decorative shrouds are attached. Full-framed seats may also include additional mounting features, typically at significant additional cost, for attaching armrests, hip restraints, and other accessories.
Another common seat construction utilizes a one-piece seat shell or pan containing both the seat base and the backrest base, typically fabricated by drawing steel or blow molding plastic. This type of seat is commonly found in off-road utility vehicles, industrial equipment, construction equipment and agricultural tractors. While one-piece seat shells fabricated using these manufacturing methods can provide a tall backrest for supporting the upper back of a seated occupant, occupant head support is typically achieved by adding a separate structure to the backrest of the shell. The strength and stiffness of a one-piece molded shell must therefore be able to withstand the loads applied to the occupant head support portion, increasing the overall cost of a seat not containing the occupant head support portion. Furthermore, integrating the occupant head support portion into the one-piece seat shell is typically not practical due to the tooling investment required to produce such a large part. Additionally, larger molded or drawn steel parts typically require high tonnage presses that are not as readily available, limiting manufacturing flexibility.
Accordingly, there is a need for a low-cost vehicle seat assembly that overcomes at least some of these drawbacks.